The present invention relates to a process for the preparation of hydroxyalkylphenyl ether or thioether compounds. More particularly, the present invention is concerned with improved catalysts for use in the preparation of such compounds by the reaction of cyclic organic carbonate compounds with phenols and thiophenols.
Carlson disclosed in U.S. Pat. No. 2,448,767 a method of hydroxyethylation wherein ethylene carbonate or ethylene sulfite was reacted with certain organic compounds including phenols and alcohols. The reaction could be carried out in the presence or in the absence of a suitable solvent, and in the presence or in the absence of a suitable catalyst. Catalysts that were disclosed included an acid (concentrated sulfuric acid or an alkyl ester of sulfuric acid), a base (alkali carbonates), or the alkali salt of a phenol. The preferred catalyst was an alkali carbonate or alkali salt of a phenol. U.S. Pat. No. 3,283,030 disclosed use of potassium carbonate as a basic catalyst in the reaction of ethylene carbonate with certain substituted phenols.
Alkali metal hydrides disclosed by U.S. Pat. No. 2,987,555 and alkali metal hydroxides disclosed by U.S. Pat. No. 2,967,892 have also been found to be effective catalysts for hydroxyalkylation reactions of ethylene carbonate with phenols and chloromethylethylene carbonate with phenols respectively.
One disadvantage associated with prior art processes using acidic or basic catalysts is the inability to use certain modified phenolic or thiophenolic compounds that are unstable under acidic or basic reaction conditions. A further disadvantage of known prior art processes is that for many purposes the catalyst must be removed from the reaction products, necessitating a subsequent purification process with its attendant expense. It would be advantageous to provide a catalyst that effectively promotes the reaction under essentially neutral conditions and which is otherwise substantially unreactive so that its presence in the final product is not disadvantageous.